// import { createApp } from 'vue'
// import './style.css'
// import App from './App.vue'

// createApp(App).mount('#app')

// 类型 类型注解   是用了类型注解之后就不可以改变类型了
export {}

let age: number = 18;
let myName: string = '黑马程序员';
let isLoading: boolean = false;
let nullValue: null = null;
let undefinedValue: undefined = undefined;